Abstract
Water production in a oil field in Syria has increased significantly in recent years. As a result oil production is currently constrained by facilities throughput. PLT surveys combined with a reservoir study on the field showed that some layers still have high hydrocarbon saturation whilst others are already swept by water. Good-quality sands are not properly swept, probably due to poor connectivity in the reservoir. By shutting of the watered-out sands the high oil saturation un-swept sands can contribute to the production. However, no mechanical through tubing technologies are currently available, due to the high expansion ratio, the high differential pressure (up to 3000 psi) and the high temperature of 150 °C.
A new particle-gel has been developed for solving the above-described problem in a cost-effective manner. The particle-gel system is a further development of the previously published gel-cement system.1 The system may be placed via coiled tubing similar to a cement squeeze. The particles in the system will create a diverting filter cake resulting in a uniform and shallow placement of the gel of typically less than 1 inch. The gel used as make up water of the slurry will be squeezed into the matrix creating a shallow matrix shut off after it is set. Selective perforation of the hydrocarbon zones can re-establish the oil production. Additionally, the shut off zones can be re-opened later in the well's life when artificial lift has been installed.
The system showed superior shut off performance in the laboratory compared to normal cement squeeze techniques. In the first field application the system was tested in vertical oil well with a static bottomhole temperature of 146 °C. A total of 186 meters of perforations were squeezed of with the particle-gel in a single attempt. Post-job PLT data confirmed that the shut off was complete because the sealed zone showed no inflow.
